Can anyone help by providing details of the action on the night(?) of 5 July 1944 involving MTB 256? In particular, what part did Sub Lt J A Peters RNVR play? Which other boats were involved, where they all from Newhaven, who was the S.O for that action, etc?

Was Sub Lt Peters assigned to a particular boat, and if so in what capacity; or were crews rotated between boats? He appears to have been listed at HMS Aggressive, but not on a particular boat.

MTB 256 was a White-built boat to a 'modified?' Vosper design. What was different about her? What happened to her?

Sub Lt Peters also served on MTB 5007 and MTB 786, Fairmile 'D's. Where were these units based, and what was their history during his time. Was there anything different about these boats?

With the help of the Daily Telegraph, it appears that I was looking for information on the wrong date. I should have asked about the night of 26 July.

I now know that the MTB was under the command of Lt Christopher Mounsey, who was killed early on in an action in the channel. I don't know what happened for the rest of the action, which other boats were involved, etc.

L C Reynolds book ‘Home Waters MTB’s & MGB’s at War 1939 -1945’ ISBN 0 7509 2518 3 has the following action on the 26th July 1944. The reference is quoted as being from MO 9084; ADM 199/264; report of CCF (Channel).

…A lull during eight nights of bad weather provided a breather from the 19th- 26th July, except for another battle with E-boats for Lt Shore’s [Commanding Officer of 474] unit of the 30th Flotilla on the 22/23 July.
On the night of the 26th Lt John Mathias [Senior Officer of 1st MTB Flotilla] was leading a unit of the 1st Flotilla in 430, with 412 and 431 in support off Cap d’Antifer and intercepted 6 E-boats. Mathias led his boats at speed through the E-boat lines; in the process 430 was rammed by S 182 and blew up. 412 (Lt Salmon) following in close order astern, could not avoid colliding with the wreckage of 430 and suffered so much damage to her Hull that she too had to be sunk later. However, S 182 also sank, and in the gun attack one other E-boat was severely damaged. Ten of 430’s crew were missing the total casualties other than these were one killed (Sub Lt D Okey); and eight wounded…

There is no mentioning of the 14th Flotilla being active on this tragic night nor the death of Lt Christopher Mounsey but our Casualty Database certainly records his death on the 26th July (just type in mounsey).
More yet to come I’m sure.

See obituary for John Peters in the Telegraph 31/12/2013- John Peters and my father Neville Gordon Oldfield were joint in command on a rotating basis under Chris Mounsey in MTB 256, 14th Flotilla under D.A Shaw - I am advised by G.Hudson that some of the details re. fuel, gun size and "ops. room are incorrect, however Mounsey was killed on July 26th 1944, and buried at sea when a support vessel drew alongside. As you say he is commemorated on the memorial at Portsmouth. Hope that this helps!

The source given against this action is M.010117. There would be an action report, but whether it still exists is another matter.
Some reports are included in Admiralty Files at The National Archive, Kew; these are prefixed ADM 198/... .

There is no mention of casualties against this action, but another note (FOBAA signal dated 26th July) says: "Damaged in action. CO killed and five ratings wounded".

In Wartime Activities
14th MTB Flotilla assets not written about this fight with a German convoy of 23/24 June 1944 at the Cape de la Hogue. MTV torpedo sank the AF-66 and several merchant ships. There are details about this fight?